In many construction machines, it is advantageous to provide a pair of frame assemblies that will pivot with respect to one another at a point that is near the center of the machine. This type of machine is known as an "articulated" machine and provides greatly increased maneuverability and handling.
One problem that exists with an articulated machines is the transfer of forces through the hitch assembly or articulation point. The two frame assemblies are connected to one another by a pinned joint, usually at upper and lower extremities. The forces that occur typically result from machine operation over uneven terrain which must pass through the hitch assembly. Also, a pair of steering cylinders typically extend between the frames to pivot the front frame with respect to the rear to provide steering for the machine. These forces also are directed through the hitch. As these forces pass through the hitch, they cause deflection of the respective portions of the hitch assembly. These deflections have been known to cause failure in the hitch assembly, primarily in the area of pin retention.
Since each hinge point rotates around a large pivot pin, the means by which the pin is secured to the two frames also becomes affected by the deflections of the two frames. In most cases the fastening means is in the form of a plurality of bolts. These bolts normally extend through at least a retaining cap that is secured to at least one end of the pin and the frame that surrounds the pin. As the forces are passed through the frame members and the pin, the deflection occurs in the area of the bolts. As this occurs, it is common for the bolts to break or loosen, which will eventually lead to the loss of the pin or the entire destruction of the hitch assembly in this area. This of course, adds to the down time of the machine and the overall cost of machine operation.
The present invention is directed to overcoming one or more of the problems listed above.